Set up for rack pulls

I’m completely new to some of the exercises on The Bridge 1.0, but I’m very excited to use this new approach to training. For rack pulls, can I literally put j cups 2" off the ground in a squat rack and do them that way or am I supposed to set the bar on the safeties? I don’t have a way to use mats at all for the next few months. Thanks!

I would put the bar on the safeties.